Heretofore, the bag wells of tire presses have generally been uninsulated, thus resulting in large losses of heat. Occasionally, in order to prevent heat loss, fiberglass insulation has been installed by hand through the narrow housing apertures. However, such is a makeshift attempt at best in that only a small portion of the bag well area was insulated, with the sides and back area of the bag well with respect to the aperture openings being uninsulated.
In order to fully insulate a bag well, the tire press operation had to be closed down, the entire bag well housing removed, insulation as in the form of fiberglass, etc., installed about the bag well, and the bag well housing reapplied. Not only was this operation time consuming, but also costly due to the close down time of the press.
U.S. Pat. No. 1,871,620 to Kraft merely relates to an insulated plate or layer along one portion of a vulcanizing cavity.
Similarly, Brundage (U.S. Pat. No. 2,266,956) contains insulating layer 27 which is mounted along one side of a vulcanizing area.
U.S. Pat. Nos. 2,358,764 and 2,358,762 to Soderquist relate to insulating the upper areas of a tire press, and not to any bag well area.
U.S. Pat. No. 3,640,653 to Laenen et al places insulation about the vulcanization chamber, particularly between the platen 9 and top plate 10 of the base. As apparent from various drawings and especially FIG. 10, it is apparent that the steam which is introduced into the air bladder comes from a remote source and is introduced into the bladder which is inflated upon introduction thereof. Once more, there is no suggestion of insulation other than the vulcanization cavity portion.
None of the above disclosures relate to the utilization or structure of an envelope which is inserted during operation of the tire press into the narrow bag well housing openings about the bag well, and inflated to create an insulation area solely about the bag well.